So, you've got a dwarf, now what do you do?

[Danielle_E.]

Marty, I find that so hard to believe. Who in their right mind would purposely breed for dwarves???? That is just pure stupidity.

 

[Marty]

I'm sending you a pm

 

[angelheart]

"Can I ask where you get this "50% of the time". If you have a non-carrier (mare) and a recessive carrier stallion or vice versa, doesn't sound to me like it would be 50% of the time."

Good question and You are right it would be alot like LWO .. What I was saying is that a carrier of a recessive gene ( assuming that we are only talking two genes here) would mathamatically donate the recessive gene 50% of the time and the dominate gene 50% of the time. That would result in passing the recessive gene 50% of the time to it's foals. That does not mean that the foal would have a 50% chance of being a dwarf. If the other parent did not carry the dwarf gene then even though 50% of the foals would carry the gene none of them would be dwarf as the dominate gene would mask the dwarf gene. If two carrier's mated then there would be a 25% chance of the resulting foal to inherit the dwarf gene from both and be a dwarf. A 50% chance of inheriting one dwarf gene and one non-dwarf gene and only be a carrier and a 25% chance that it would not inherit the dwarf gene from either parent and not be a dwarf or a carrier.

If it turns out that there are multiple genes involved with creating a dwarf then the mathmatics will get much foggier. The scenrios that I presented would only apply if there are only two genes ( one from each parent)involved in determining whether or not a minaiture horse is a genetic dwarf .. one being a dominate gene and the other a recessive gene.

 

[Danielle_E.]

I was under the impression, having read about human dwarfism that it has to do with two genes from each parent, meaning each parent has a set of genes so a total of 4 are in play. Now one of the genes could be the ones causing the problem, while the other not, That is why whenever i have researched it they always mention 25% chance, not 50% chance. And if this is correct that is what I was saying. You could have two parents each carrying a recessive gene but neither when mated contributing that gene to the foal which would mean the foal is not a carrier. I need to do some more reading

because now i am totally confused OH!

 

[Dona]

I was under the impression, having read about human dwarfism that it has to do with two genes from each parent, meaning each parent has a set of genes so a total of 4 are in play. Now one of the genes could be the ones causing the problem, while the other not, That is why whenever i have researched it they always mention 25% chance, not 50% chance. And if this is correct that is what I was saying. You could have two parents each carrying a recessive gene but neither when mated contributing that gene to the foal which would mean the foal is not a carrier. I need to do some more reading

because now i am totally confused OH!

You are right Danielle....but that is exactly what Angelheart is saying. EACH individual horse carries two genes.

Lets say D = Dwarf and N = Normal

Dwarf carrier........ N + D

Non Carrier...........N + N

Dwarf.................. D + D

If the horse is only a "carrier" it will have (1) non-Dwarf gene and (1) Dwarf gene. It will throw one or the other....meaning 50% of the time it will throw the Dwarf gene.

Now add a "mate" to the mix who is a "non-carrier"....it would reduce the chance to 25%.

N + N + N + D = 25% chance of passing the Dwarf gene.

If you breed a carrier to a carrier....it would again be 50%.

N + D + N + D = 50% chance of passing the Dwarf gene.

Now, Heaven forbid, some idiot wants to breed a full-blown Dwarf...you would have 100% of passing the Dwarf gene!

Even if bred to a non-carrier, you would still produce a "carrier" of the Dwarf gene.

And if bred to a "carrier"....you would have 75% change of producing a full-blown Dwarf! OH!

And I repeat what Angelheart said....."If it turns out that there are multiple genes involved with creating a dwarf then the mathmatics will get much foggier. The scenrios that I presented would only apply if there are only two genes ( one from each parent)involved in determining whether or not a minaiture horse is a genetic dwarf .. one being a dominate gene and the other a recessive gene."

 

[Candice]

I'm new to miniatures. Last year I purchased my mares bred. My one little mare produced a beautiful black and white paint colt. Very tiny. I thought his head looked a little "domey" but everyone who saw him, including my vets concluded that he was a nice little colt and not a dwarf. By the time he was 3- 3 1/2 mos old his minimal dwarfism was becoming very apparent and at an alarming rate. His bite went off. He has a serious problem with one leg that is being treated at UF.

My problem is that I'd already rebred his dam to my stallion. His dam is a beautiful correct mare. When I looked up her produce record she has had several nice foals. Her sire is one of the foremost stallions in miniature history. On her dams' side however, several generations back is a name we all know and don't want to see.

Now, as a novice horse buyer I didn't think to ask the breeder if she'd ever produced a dwarf foal. This colts sire is a regional reserve champion. I don't think the people who bred her ever anticipated she would produce a dwarf foal.

There is a lot of talk about visible traits, but how about the horses that show no visible traits, have produced numerous foals and then out of nowhere a dwarf foal is delivered.

I have chosen not to pursue the matter with the breeder. They sold the stallion just prior to me purchasing the mare. I own the mare. I am concerned about what she will produce this year. I'm worried for her as well as her unborn foal.

As far as my colt. He's in my avatar. We LOVE him. His issues are minimal. He loves parades and being out with people and as soon as his leg is better he will be back out in the world making people happy. People are drawn to him and love him. I do also take the time to explain to people about what he is and his issues and that he is not what we strive to breed.

Its a tough situation with no "absolute" answers. More has to be learned.

 

[Marty]

Thank you Dona for putting it into terms I can understand better

 

[Michelle@wescofarms]

One of my first minis we purchased as a pet (still here and well loved) is a 38" gelding. He had two siblings that were dwarves (found out later), one that died in foaling. Was his father a carrier - to me yes. Is my gelding very likely too, but to look at him he's more big pony looking than dwarf so?? Did the breed stop breeding his sire no he was sold to someone else.

As for my own personal peace of mind, I would want to know about any downline dwarves from our breeding program.

What would I do regarding outside breedings, hard to say. Some people would want to know others not, you can't be responsible for their ethics.

Unfortunately until we can test and really have many geneations of accurate DNA/PQ tested horses it's a crap shoot as to parentage and who/why dwarfism happens.

 

[Whitestar]

While it is being discussed, I would like to ad a few more questions in the mix. What happens if a test is found & it turns out that 25, 50,75%...maybe all minature horses turn out to carry some form of the gene. What happens if the horse you have been breeding for years that have never produced a dwarf turns out to carry the gene? There are some people that think that the gene is in all miniatures,. there are some that think it is in only a few, & some think it only matters if you breed two together that carry the gene...This discussion came up a lot amongst breeders when I was breeding, with very very different answers from all sorts of people.I dont think anyone really wants to breed for a dwarf ( although there is a market for them in petting zoos & as house pets as others have mentioned...very sad...)& any breeder would want to minimize the risk of breeding one, however what happens if the test is mandatory & all of sudden your herd is now 50% or 25% or even 0% of what you started with? There are folks that feel very secure that it wont happen to them because they have not produced a dwarf before, but as most breeders find out, it could happen at any time. And frankly....until there is a test.. we dont know what is in a horses genetics.

. I would be interested in seeing what you folks think.

 

[nootka]

I think with the test, we could better utilize the results of those tests to minimize the risks in the most outstanding of individuals.

Say, for example, the most perfect-looking Miniature horse was born, yet the testing proved that it had a 50% chance of passing on the dwarf gene. What might be worth the risk is to try, via regular breeding or even the embryo transfer, to get a sampling of her foals when bred to the most perfect, "safe" stallions.

Test the offspring and further reduce your risks, in a perfect world.

I don't know enough about the QH or Arabian industry, or Paints, but they already have similar situations with testing available. What appears to me on a superficial scan is that you will have people that will ignore the testing, will continue to breed what they want and sell without full disclosure of test results to uninformed or other like-minded people.

Even if 100% of the miniatures were found to have something in common (which I would highly doubt, because we come from Shetlands and the like, and I know not all of them could be hiding it...or could they?) which would make them able to produce dwarfs, we could use that technology to better reduce the risk.

Marty, could you send me the link of the purposeful dwarf breeders? I'm only curious more for the reason that they are likely unashamed and I could see the parents, etc. I'm not going to contact the people or anything. (or anyone else that knows it)

Likewise, I have a link to a farm that I know that does the same, and sells the foals as micro minis.

I would love to see a test available, no matter the results.

Liz

 

[Miniv]

I think what also needs to be discussed and tested is that there are TWO different types of dwarfism in miniature horses. And there could very possibly be two different sets of DNA's because of this.

MA

 

[Arion Mgmt]

MA,

Which two types of dwarfism are you referring to? I believe there are more types than that.

Can you explain to me what you mean by these miniatures having possibly two different genomes and how that is possible??

John